Extended calibration range for prompt photon emission in ion beam irradiation

Monitoring the dose delivered during proton and carbon ion therapy is still a matter of research. Among the possible solutions, several exploit the measurement of the single photon emission from nuclear decays induced by the irradiation. To fully characterize such emission the detectors need development, since the energy spectrum spans the range above the MeV that is not traditionally used in medical applications. On the other hand, a deeper understanding of the reactions involving gamma production is needed in order to improve the physic models of Monte Carlo codes, relevant for an accurate prediction of the prompt-gamma energy spectrum.This paper describes a calibration technique tailored for the range of energy of interest and reanalyzes the data of the interaction of a 80MeV/u fully stripped carbon ion beam with a Poly-methyl methacrylate target. By adopting the FLUKA simulation with the appropriate calibration and resolution a significant improvement in the agreement between data and simulation is reported.Comment: 4 pages, 7 figures, Submitted to JINS

Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center) beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presente

Proposal of an experimental test at DAΦNE for the low emittance muon beam production from positrons on target

We present in this paper the proposal of an experimental test at DAΦNE of the positronring-plus-target scheme foreseen in the Low EMittance Muon Accelerator. This test would be a validation of the on-going studies for LEMMA and it would be synergic with other proposals at DAΦNE after the SIDDHARTA run. We discuss the beam dynamics studies for different targets inserted in a proper location through the ring, i.e. where the beam is focused and dispersion-free. Optimization of beam parameters, thickness and material of target and optics of the target insertion are shown as well. The development of the existent diagnostic needed to test the behavior of the circulating beam is described together with the turn-by-turn measurement systems of charge, lifetime and transverse size. Measurements on the temperature and thermo-mechanical stress on the target are also under study

Routine immunization of older adults and frail people during the SARS-COV2-pandemic in Italy: a national survey by Italia Longeva

Despite the availability of safe and effective vaccines, older adults and frail people (OAFs) remain far from accomplishing the recommended coverage targets. The SARS-CoV-2 pandemics strongly affected the supply and coverage of routine vaccines, especially for OAFs, but it also suggested innovative solutions to catch up with the immunization schedules we were late with. Italia Longeva, the National Association for Active Longevity established in 2011 by the Ministry of Health, realized this research aiming to collect and share local good practices for the routine immunization of OAFs implemented during the SARS-CoV-2 pandemic. We surveyed 12 local health directors from 9 Regions (with a potential covered area of about 24 million inhabitants) between January and March 2021. Starting from the 2018 Thomas and Lorenzetti’s Cochrane Review, a “snowball” search of scientific and grey literature was performed to create and validate a 27-items semi-structured questionnaire used to collect information during the interviews. Full methods are available online (https://www.italialongeva.it/). A wide range of organizational models and settings for immunization supply to OAFs were found across regions. The local implementation of the 27 interventions to increase vaccination coverage among OAFs identified through the literature review ranges from 0% to 100%, with higher rates for interventions targeting the professionals (i.e. audits), lower when aimed to increase the vaccine offer (i.e. active calls) or its accessibility (i.e. home vaccination). Seven good local practices have been identified and described: Mass Vaccination Centre; drivethrough Vaccination; Mobile vaccination clinics; co-administration; collaboration within different organization; Electronic immunization registries; standardized immunization pathways. Literature suggests many effective interventions to improve immunization of OAFs, but their implementation at local level shows huge heterogeneity. Providers should combine several interventions adequate to the specific context (organizational models, interoperability, urban or rural context, etc) and share good practice

First Ex-Vivo Validation of a Radioguided Surgery Technique with beta- Radiation

Purpose: A radio-guided surgery technique with beta- -emitting radio-tracers was suggested to overcome the effect of the large penetration of gamma radiation. The feasibility studies in the case of brain tumors and abdominal neuro-endocrine tumors were based on simulations starting from PET images with several underlying assumptions. This paper reports, as proof-of-principle of this technique, an ex-vivo test on a meningioma patient. This test allowed to validate the whole chain, from the evaluation of the SUV of the tumor, to the assumptions on the bio-distribution and the signal detection. Methods: A patient affected by meningioma was administered 300 MBq of 90Y-DOTATOC. Several samples extracted from the meningioma and the nearby Dura Mater were analyzed with a beta- probe designed specifically for this radio-guided surgery technique. The observed signals were compared both with the evaluation from the histology and with the Monte Carlo simulation. Results: we obtained a large signal on the bulk tumor (105 cps) and a significant signal on residuals of $\sim$0.2 ml (28 cps). We also show that simulations predict correctly the observed yields and this allows us to estimate that the healthy tissues would return negligible signals (~1 cps). This test also demonstrated that the exposure of the medical staff is negligible and that among the biological wastes only urine has a significant activity. Conclusions: This proof-of-principle test on a patient assessed that the technique is feasible with negligible background to medical personnel and confirmed that the expectations obtained with Monte Carlo simulations starting from diagnostic PET images are correct.Comment: 17 pages, 4 Figs, Accepted by Physica Medic

Study of the time and space distribution of beta+ emitters from 80 MeV/u carbon ion beam irradiation on PMMA

Proton and carbon ion therapy is an emerging technique used for the treatment of solid cancers. The monitoring of the dose delivered during such treatments and the on-line knowledge of the Bragg peak position is still a matter of research. A possible technique exploits the collinear 511\ \kilo\electronvolt photons produced by positrons annihilation from $\beta^+$ emitters created by the beam. This paper reports rate measurements of the 511\ \kilo\electronvolt photons emitted after the interactions of a 80\ \mega\electronvolt / u fully stripped carbon ion beam at the Laboratori Nazionali del Sud (LNS) of INFN, with a Poly-methyl methacrylate target. The time evolution of the $\beta^+$ rate was parametrized and the dominance of $^{11}C$ emitters over the other species ($^{13}N$, $^{15}O$, $^{14}O$) was observed, measuring the fraction of carbon ions activating $\beta^+$ emitters $A_0=(10.3\pm0.7)\cdot10^{-3}$. The average depth in the PMMA of the positron annihilation from $\beta^+$ emitters was also measured, D_{\beta^+}=5.3\pm1.1\ \milli\meter, to be compared to the expected Bragg peak depth D_{Bragg}=11.0\pm 0.5\ \milli\meter obtained from simulations

Charged particle's flux measurement from PMMA irradiated by 80 MeV/u carbon ion beam

Hadrontherapy is an emerging technique in cancer therapy that uses beams of charged particles. To meet the improved capability of hadrontherapy in matching the dose release with the cancer position, new dose monitoring techniques need to be developed and introduced into clinical use. The measurement of the fluxes of the secondary particles produced by the hadron beam is of fundamental importance in the design of any dose monitoring device and is eagerly needed to tune Monte Carlo simulations. We report the measurements done with charged secondary particles produced from the interaction of a 80 MeV/u fully stripped carbon ion beam at the INFN Laboratori Nazionali del Sud, Catania, with a Poly-methyl methacrylate target. Charged secondary particles, produced at 90$\degree$ with respect to the beam axis, have been tracked with a drift chamber, while their energy and time of flight has been measured by means of a LYSO scintillator. Secondary protons have been identified exploiting the energy and time of flight information, and their emission region has been reconstructed backtracking from the drift chamber to the target. Moreover a position scan of the target indicates that the reconstructed emission region follows the movement of the expected Bragg peak position. Exploting the reconstruction of the emission region, an accuracy on the Bragg peak determination in the submillimeter range has been obtained. The measured differential production rate for protons produced with $E^{\rm Prod}_{\rm kin} >$ 83 MeV and emitted at 90$\degree$ with respect to the beam line is: $dN_{\rm P}/(dN_{\rm C}d\Omega)(E^{\rm Prod}_{\rm kin} > 83 {\rm ~MeV}, \theta=90\degree)= (2.69\pm 0.08_{\rm stat} \pm 0.12_{\rm sys})\times 10^{-4} sr^{-1}$.Comment: 13 pages, 9 figure

Experimental validation of an innovative approach in biokinetics study for personalised dosimetry of molecular radiation therapy treatments

: One of today's main challenges in molecular radiation therapy is to assess an individual dosimetry that allows treatment to be tailored to the specific patient, in accordance with the current paradigm of 'personalized medicine'. The evaluation of the absorbed doses for tumor and organs at risk in molecular radiotherapy is typically based on MIRD schema acquiring few experimental points for the assessement of biokinetic parameters. WIDMApp, the wearable individual dose monitoring apparatus, is an innovative approach for internal dosimetry based on a wearable radiation detecting system for individual biokinetics sampling, a Monte Carlo simulation for particle interaction, and an unfolding algorithm for data analysis and integrated activity determination at organ level. A prototype of a WIDMApp detector element was used to record the photon emissions in a body phantom containing 3 spheres with liquid sources (18F,64Cu and99mTc) to simulate organs having different washout. Modelling the phantom geometry on the basis of a CT scan imaging, the Monte Carlo simulation computed the contribution of each emitting sphere to the signal detected in 3 positions on the phantoms surface. Combining the simulated results with the data acquired for 120 h, the unfolding algorithm deconvolved the detected signal and assessed the decay half-life (T1/2) and initial activity values (A(0)) that best reproduces the observed exponential decays. A 3%-18% level of agreement is found between the actualA(0) andT1/2values and those obtained by means of the minimization procedure based on the Monte Carlo simulation. That resulted in an estimation of the cumulated activity <15%. Moreover, WIDMApp data redundancy has been used to mitigate some experimental occurrences that happened during data taking. A first experimental test of the WIDMApp approach to internal radiation dosimetry is presented. Studies with patients are foreseen to validate the technique in a real environment

90Y-DOTA-nimotuzumab: synthesis of a promising β⁻ radiopharmaceutical

BACKGROUND: Nimotuzumab is a humanized anti-epidermal growth factor receptor (EGFR) monoclonal antibody, nowadays used for tumour immunochemotherapy. This study aimed to label the conjugate DOTA-nimotuzumab with yttrium-90, in order to provide a beta- emitting radioimmunoconjugate (90Y-DOTA-nimotuzumab) potentially useful to assess the feasibility of a new radio-guided surgery approach.METHODS: The synthesis of 90Y-DOTA-nimotuzumab was performed in two days. Nimotuzumab was conjugated with a 50 fold excess of DOTA and then labelled with 90Y3+. The 90Y-DOTA-nimotuzumab preparation was optimized considering several parameters such as pH, temperature and reaction volume. Moreover, the 90Y-DOTA-nimotuzumab stability was evaluated in human plasma.RESULTS: The radioimmunoconjugate 90Y-DOTA-nimotuzumab was obtained with a radiochemical purity greater than 96%, and showed a good stability at 20°C as well as at 37°C in human plasma.CONCLUSIONS: The optimized conditions for a mild and easy preparation of 90Y-DOTA-nimotuzumab joined to a promising stability under physiological conditions suggest to propose this radioimmunoconjugate as a potential diagnostic radiopharmaceutical for beta- radio-guided surgery

Secondary radiation measurements for charged particle therapy monitoring: fragmentation of therapeutic He, C and O ion beams impinging on a PMMA target

In Charged Particle Therapy (CPT), besides protons, there has been recently a growing interest in 4He, 12C and 16O beams. The secondary radiation produced in the interaction of those beams with a patient could be potentially used for on‐line monitoring of range uncertainties in order to fully exploit the advantages of those light ions resulting from increased Radio Biological Effectiveness, reduced multiple scattering and Oxygen Enhancement Ratio. The study and precise characterization of secondary radiation (beta+, prompt gamma, charged fragments) is the cornerstone of any R&D activity aiming for online monitoring development and purpose of the analysis presented here